Day 17 revisits Day 5's running sandwich and swaps the finisher for the floor. The circuit is 20 butt kicks, 20 high knees, 20 butt kicks and 20 climbers - straight through for a set, 2 minutes rest, 3, 5 or 7 sets by level. Three running blocks standing, as before, then a running block in plank.
Butt kicks open and return, heels flicking up toward the glutes, with high knees between them driving the knees up in front - 60 running steps in a set with the emphasis alternating between hamstrings and hip flexors. Where Day 5 finished with split jacks, today it finishes with climbers: drop into a high plank and run the knees toward the chest, 10 per leg. It is a smaller change than it looks on paper and a bigger one than it feels in the body: the split jack asked the legs to jump one more time, the climber asks the arms and core to hold you up while the legs keep running. Same three opening exercises, completely different ending.
Butt kicks quick and light with the heels reaching high. High knees to hip height, arms pumping. In climbers, hands under the shoulders, hips low and level, knee driving toward the chest each rep - and take a second to set the plank properly before the first rep rather than dropping straight into a sloppy one.
Three blocks on your feet and one on your hands - Day 5's finisher jumped, this one climbed.
Make it Harder: Do the climbers with the knee driving to the outside of the same-side elbow on every rep - a wider, harder track for the hips.
Make it Easier: Turn the climbers into slow step-ins - one foot forward, back, then the other - and stand up for a breath before the block if you need it.
